Ecosystem-based management requires the development of indicators that allow anthropogenic impacts to be detected against the background of natural variation. Size-based community metrics are potentially useful indicators because of their theoretical foundation and practical utility. Temporal and spatial patterns in size-based community metrics for Celtic Sea fish are described and calculated using data from the English groundfish survey of the area (1987-2003). The results reveal that the size structure of the community has changed over time, and that a decrease in the relative abundance of larger fish was accompanied by an increase in smaller fish (4-25 g). Temporal analyses of the effects of fishing and climate variation suggest that fishing generally has had a stronger effect on size structure than changes in temperature. Therefore, size-based metrics respond clearly to the effects of fishing even in variable environments, reflecting the ubiquity of size-based processes in defining community structure and responses to mortality. Spatial analyses were inconclusive, probably owing to the limited area for which fishing effort, temperature, and survey data were all available.

Item Type:	Refereed Article
Keywords:	ecological indicators, climate change and fishing impacts
Research Division:	Environmental Sciences
Research Group:	Climate change impacts and adaptation
Research Field:	Ecological impacts of climate change and ecological adaptation
Objective Division:	Environmental Management
Objective Group:	Management of Antarctic and Southern Ocean environments
Objective Field:	Assessment and management of Antarctic and Southern Ocean ecosystems
UTAS Author:	Blanchard, JL (Professor Julia Blanchard)
UTAS Author:	Tidd, A (Dr Alexander Tidd)
ID Code:	100511
Year Published:	2005
Web of Science® Times Cited:	147
Deposited By:	Sustainable Marine Research Collaboration
Deposited On:	2015-05-18
Last Modified:	2017-05-04
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